NETFILTER PACKET FLOW (kernel):
DROP will not warn
REJECT will let them know its closed
example:
(RULE CHECK CHAIN) (THE RULE, WHAT TO DO)
iptables -t filter -A INPUT -s …
Iptables howto
IPTABLES basic commands
List current rules:
# iptables -L -v
Remove all previous rules:
# iptables -F
Don’t disconnect ESTABLISHED connections:
# iptables -A INPUT -m state –state ESTABLISHED,RELATED -j …